The CAS Registry Mumber 87215-96-1 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 8,7,2,1 and 5 respectively; the second part has 2 digits, 9 and 6 respectively. Calculate Digit Verification of CAS Registry Number 87215-96: (7*8)+(6*7)+(5*2)+(4*1)+(3*5)+(2*9)+(1*6)=151 151 % 10 = 1 So 87215-96-1 is a valid CAS Registry Number.